1. Field of the Invention
The present invention relates to a cutting machine for cutting a cutting sheet moving in the X-axis direction into a given shape using a cutter moving in the Y-axis direction and, in particular, to an elevating mechanism provided in such a cutting machine for contacting and separating the cutter with respect to the cutting sheet.
Further, the present invention relates to a structure for arranging an origin detecting sensor which is used to detect the origin of a carriage with a cutter mounted thereon in a cutting machine.
2. Description of the Related Art
Generally, as a cutting machine for cutting a cutting sheet into a given shape, there is known a cutting machine in which not only a carriage is moved in the X- and Y-axis directions with respect to a stationary cutting sheet but also the carriage is moved in the Z-axis direction to thereby contact and separate a cutter with respect to the cutting sheet, whereby the cutting sheet is cut into a given shape.
However, the above-mentioned cutting machine, in which the cutter is moved directly in the X- and Y-axis directions, is complicated in structure as well as requires an expensive bearing and troublesome wire arrangement. Especially, a mechanism for moving up and down a carriage with a cutter in the Z-axis direction requires high accuracy and is thereby inevitably complicated in structure. That is, because such direct-moving mechanism or linear mechanism moves the cutter up and down, there is employed a structure that a cutter holder itself is guided linearly with respect to the carriage. For this reason, a guide for guiding the cutter holder is requested to have such high-accuracy parallelism that, when it moves, it is can be prevented against play (in the case of insufficient parallelism, when it is used for a long period of time, it plays heavily and is thereby worn excessively); and, therefore, the manufacturing cost of the guide is expensive.
Further, in a related cutting machine when the cutting machine cuts out a character or a figure from a cutting sheet, the origin of a carriage (cutter) is previously detected to thereby control the position of the carriage. In such position control, the amount of movement of the carriage up to the then position of the carriage is determined with the origin position of the carriage as the standard to thereby control the amount of rotation of a carriage driving motor. For this purpose, when the power is turned on, it is necessary to detect the origin position of the carriage. In order to detect the origin position of the carriage, a sensor lever is disposed on the carriage and also, in order to be able to confirm that the carriage has returned to the origin by detecting the sensor lever, there is disposed an origin detecting sensor on the main body of the cutting machine.
However, in the above-mentioned cutting machine, once the origin is detected, it is not necessary to detect the origin unless the power is turned off. Therefore, when the cutting machine is put into its normal cutting operation, in order to prevent the sensor lever from interfering (colliding) with the origin detecting sensor, the start point of movement of the carriage must be set at a position which is moved by a given amount from the origin, which makes it inevitable to spread the entire width of the cutting machine by an amount equivalent to such space.
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional cutter elevating mechanism. Accordingly, it is a first object of the invention to provide a cutter elevating mechanism in a cutting machine which is simple in structure and is able to operate with sufficient accuracy.
Further, it is a second object of the invention to provide a structure for arranging an origin detecting sensor in a cutting machine, which can eliminate the need for provision of a space for relief of a sensor lever disposed so as to detect the origin of a carriage to thereby reduce the size of the cutting machine.
In order to attain the first object, the present invention provides a cutter elevating mechanism in a cutting machine for cutting a belt-shaped cutting sheet moving in the X-axis direction into a given shape with a cutter moving in the Y- and Z-axis directions. The following are features of the present invention. A Y-axis shaft is disposed in the Y-axis direction above the cutting sheet. A carriage with a cutter mounted on the leading end thereof is disposed on the Y-axis shaft in such a manner that it can be slid along the Y-axis shaft. A sub-shaft parallel to the Y-axis shaft is disposed so as to penetrate the leading end side of the carriage. The two ends of the Y-axis shaft and the sub-shaft are respectively connected and fixed to each other through connecting frames, whereby the sub-shaft is moved up and down using an elevating device to thereby move the cutter up and down in the Z-axis direction with respect to the cutting sheet.
Further, in order to attain the second object, the present invention provides a structure for an arrangement of an origin detecting sensor in a cutting machine for cutting a belt-shaped cutting sheet moving in the X-axis direction into a given shape with a cutter moving in the Y- and Z-axis directions. The following are features of the present invention. A Y-axis shaft is disposed in the Y-axis direction above the cutting sheet. A carriage with a cutter mounted on the leading end thereof is disposed on the Y-axis shaft in such a manner that it can be slid along the Y-axis shaft in the Y-axis direction. A sub-shaft parallel to the Y-axis shaft is disposed so as to penetrate the leading end side of the carriage. The two ends of the Y-axis shaft and the sub-shaft are respectively connected and fixed to each other through connecting frames to thereby form a frame assembly. A sensor lever is disposed on the carriage so as to project in the origin direction. On the connecting frames, there is arranged an origin detecting sensor for detecting the sensor lever when the carriage is moved in the origin direction, whereby the sub-shaft is moved in the vertical direction using an elevating device to thereby swing the frame assembly up and down about the Y-axis shaft and move the cutter up and down in the Z-axis direction with respect to the cutting sheet. The origin detecting sensor and the carriage can be moved in the vertical direction in synchronization with each other.